BackgroundExtended systemic lymphadenectomy D2 is standard procedure for surgical treatment of advanced gastric cancer AGC although less extensive lymphadenectomy D1 can be applied to early gastric cancer. Complete D2 lymphadenectomy is the mandatory procedure for studies that evaluate surgical treatment results of AGC. However, the actual extent of D2 lymphadenectomy varies among surgeons because of a lacking consensus on the anatomical definition of each lymph node station. This study is aimed to develop a consensus for D2 lymphadenectomy and also to qualify surgeons that can perform both laparoscopic and open D2 gastrectomy.

Methods-DesignThis KLASS-02-QC is a prospective, observational, multicenter study to qualify the surgeons that will participate in the KLASS-02-RCT, which is a prospective, randomized, clinical trial comparing laparoscopic and open gastrectomy for AGC. Surgeons and reviewers participating in the study will be required to complete a questionnaire detailing their professional experience and specific gastrectomy surgical background-training, and the gastrectomy metrics of their primary hospitals. All surgeons must submit three laparoscopic and three open D2 gastrectomy videos, respectively. Each video will be allocated to five peer reviewers; thus each surgeon’s operations will be assessed by a total of 30 reviews. Based on blinded assessment of unedited videos by experts’ review, a separate review evaluation committee will decide whether or not the evaluated surgeon will participate in the KLASS-02-RCT. The primary outcome measure is each surgeon’s proficiency, as assessed by the reviewers based on evaluation criteria for completeness of D2 lymphadenectomy.

DiscussionWe believe that our study for standardization of D2 lymphadenectomy and surgical quality control KLASS-02-QC will guarantee successful implementation of the subsequent KLASS-02-RCT study. After making consensus on D2 lymphadenectomy, we developed evaluation criteria for completeness of D2 lymphadenectomy. We also developed a unique surgical standardization and quality control system that consists of recording unedited surgical videos, and expert review according to evaluation criteria for completeness of D2 lymphadenectomy. We hope our systematic approach will set a milestone in surgical standardization that is essential for surgical clinical trials. Additionally, our methods will serve as a novel system for educating surgeons and assessing surgical proficiency.